Mammalian bone tissue contains one or more proteinaceous materials, presumably active during growth and natural bone healing that can induce a developmental cascade of cellular events resulting in bone formation. Various developmental factors are present in bone. These include bone morphogenetic proteins (BMPs), bone inductive proteins, bone growth factors, osteogenic proteins, or osteoinductive proteins. While these proteins have different effects and functions, these proteins will be referred to collectively herein as osteoinductive factors.
These osteoinductive factors are present within the compound structure of cortical bone and are present at very low concentrations, for example, 0.003% by weight. Osteoinductive factors direct the differentiation of pluripotent mesenchymal cells into osteoprogenitor cells that form osteoblasts. Proper demineralization of cortical bone exposes these osteoinductive factors in bone rendering it osteoinductive.
The rapid and effective repair of bone defects caused by injury, disease, wounds, or surgery has long been a goal of orthopedic surgery. Toward this end, a number of materials have been used or proposed for use in the repair of bone defects. The biological, physical, and mechanical properties of the materials are among the major factors influencing their suitability and performance in various orthopedic applications.
Autologous cancellous bone (ACB) has long been considered the gold standard for bone grafts. ACB includes osteogenic cells, which have the potential to assist in bone healing, is nonimmunogenic, and has structural and functional characteristics that are appropriate for a healthy recipient. Some people do not have adequate amounts of ACB for harvesting. These people include, for example, older people and people who have had previous surgeries. A majority of people, however, do have adequate amounts of ACB for harvesting. There may nevertheless be reluctance to harvest ACB because of pain at the harvest site and potential donor site morbidity.
Conventionally, bone tissue regeneration is achieved by filling a bone defect with a bone material, for example, a bone graft. Over time, the bone graft is incorporated by the host and new bone remodels the bone graft. Bone material can include bone from the patient's own body or artificial, synthetic, or natural substitute bone material.
Demineralized bone matrix (DBM) is bone material commonly used in orthopedic procedures to substitute for, or extend the volume of, an autograft or allograft bone. Demineralized bone matrix is typically derived from cadavers. The bone is removed aseptically and/or treated to kill any infectious agents. The bone is then particulated by milling or grinding and then the mineral components are extracted, for example, by soaking the bone in an acidic solution.
To deliver the bone material to the bone defect, often times the bone material is mixed with liquid or a therapeutic agent, powder, fiber or granular material. Mixing devices that are currently available are cumbersome to use and do not allow uniform and easy mixing of material. Further, transfer of bone material to the delivery device is often done by crude packing of the bone delivery device and there is unwanted spillage of bone material out of the device, which may increase the risk of contamination of the bone material. Currently available delivery devices often lack precision in measuring the bone material for delivery to the target bone defect.
It would therefore be desirable to provide a bone material dispensing apparatus that allows easy and precise measuring and mixing of bone material. Further, a bone material dispensing apparatus that allows easier loading of the delivery device, which reduces the risk of contamination and spillage of bone material from the delivery device would also be desirable.